Using light to manipulate neuron excitability

MIT and Harvard University researchers have devised a way to achieve long-term changes in neuron activity. With their new strategy, they can use light exposure to change the electrical capacitance of the neurons’ membranes, which alters their excitability (how strongly or weakly they respond to electrical signals).
Photo Credit: SFLORG stock image

Nearly 20 years ago, scientists developed ways to stimulate or silence neurons by shining light on them. This technique, known as optogenetics, allows researchers to discover the functions of specific neurons and how they communicate with other neurons to form circuits.

Building on that technique, MIT and Harvard University researchers have now devised a way to achieve longer-term changes in neuron activity. With their new strategy, they can use light exposure to change the electrical capacitance of the neurons’ membranes, which alters their excitability (how strongly or weakly they respond to electrical and physiological signals).

Changes in neuron excitability have been linked to many processes in the brain, including learning and aging, and have also been observed in some brain disorders, including Alzheimer’s disease.

“This new tool is designed to tune neuron excitability up and down in a light-controllable and long-term manner, which will enable scientists to directly establish the causality between the excitability of various neuron types and animal behaviors,” says Xiao Wang, the Thomas D. and Virginia Cabot Assistant Professor of Chemistry at MIT, and a member of the Broad Institute of MIT and Harvard. “Future application of our approach in disease models will tell whether fine-tuning neuron excitability could help reset abnormal brain circuits to normal.”

Jawbone may represent earliest presence of humans in Europe

For over a century, one of the earliest human fossils ever discovered in Spain has been long considered a Neandertal. However, new analysis from an international research team, including scientists at Binghamton University, State University of New York, dismantles this century-long interpretation, demonstrating that this fossil is not a Neandertal; rather, it may actually represent the earliest presence of Homo sapiens ever documented in Europe.

In 1887, a fossil mandible was discovered during quarrying activities in the town of Banyoles, Spain, and has been studied by different researchers over the past century. The Banyoles fossil likely dates to between approximately 45,000-65,000 years ago, at a time when Europe was occupied by Neandertals, and most researchers have generally linked it to this species.

“The mandible has been studied throughout the past century and was long considered to be a Neandertal based on its age and location, and the fact that it lacks one of the diagnostic features of Homo sapiens: a chin,” said Binghamton University graduate student Brian Keeling.

The new study relied on virtual techniques, including CT scanning of the original fossil. This was used to virtually reconstruct missing parts of the fossil, and then to generate a 3D model to be analyzed on the computer.

Many genes linked to alcohol and tobacco use are shared among diverse ancestries

Penn State College of Medicine researchers co-led a large genetic study that identified more than 2,300 genes predicting alcohol and tobacco use. They said that many of these genes were similar among people with diverse ancestries.
Photo Credit: Pavel Danilyuk

Penn State researchers co-led a large genetic study that identified more than 2,300 genes predicting alcohol and tobacco use after analyzing data from more than 3.4 million people. They said a majority of these genes were similar among people with European, African, American and Asian ancestries.

Alcohol and tobacco use are associated with approximately 15% and 5% of deaths worldwide, respectively, and are linked with chronic conditions like cancer and heart disease. Although the environment and culture can affect a person’s use and the likelihood of becoming addicted to these substances, genetics is also a contributing factor, according to Penn State College of Medicine researchers. They helped identify around 400 genes that are associated with certain alcohol and tobacco use behaviors in people in a prior research study.

“We’ve now identified more than 1,900 additional genes that are associated with alcohol and tobacco use behaviors,” said Dajiang Liu, professor and vice chair for research in the Department of Public Health Sciences. “A fifth of the samples used in our analysis were from non-European ancestries, which increases the relevance of these findings to a diverse population.”

It’s colossal: Creating the world’s largest dilution refrigerator

Colossus will offer 5 cubic meters of space and cool components to around 0.01K.
Photo Credit: Ryan Postel, Fermilab

While the refrigerator in your kitchen gets cold enough to prevent your leftovers from spoiling, dilution refrigerators used for quantum computing research cool devices near the coldest physical temperature possible. Now at the U.S. Department of Energy’s Fermi National Accelerator Laboratory, researchers are building Colossus: It will be the largest, most powerful refrigerator at millikelvin temperatures ever created.

Fermilab is known for its massive experiments, and Colossus will fit right in. Researchers from the Fermilab-hosted Superconducting Quantum Materials and Systems Center need lots of room at cold temperatures to achieve their goal of building a state-of-the-art quantum computer.

Unlike a kitchen refrigerator, which compresses gases called refrigerants to cool food, a dilution refrigerator uses a mixture of helium isotopes to create temperatures close to absolute zero, or zero kelvin: the coldest temperature imaginable in physics, which is physically impossible to reach.

“With the cooling power and volume that Colossus will provide, SQMS researchers will have unprecedented space for our future quantum computer and many other quantum computing and physics experiments,” said Matt Hollister, the lead technical expert on this project. “Colossus is named after the first electronic programmable computer, which was constructed in the 1940s for codebreaking. It was a historic milestone in the history of computing and seemed like an appropriate name for the size of our new refrigerator.”

New branch on tree of life includes ‘lions of the microbial world’

On the left is a starving provoran. On the right, it has engulfed its prey.
Photo Credit: Tikhonenkov, Mikhailov, Gawryluk, Belyaev, Mathur, Karpov, Zagumyonnyi, Borodina, Prokina, Mylnikov, Aleoshin, and Keeling, Nature

There’s a new branch on the tree of life and it’s made up of predators that nibble their prey to death.

These microbial predators fall into two groups, one of which researchers have dubbed “nibblerids” because they, well, nibble chunks off their prey using tooth-like structures. The other group, nebulids, eat their prey whole. And both comprise a new ancient branch on the tree of life called “Provora,” according to a paper published today in the journal Nature.

Microbial lions

Like lions, cheetahs, and more familiar predators, these microbes are numerically rare but important to the ecosystem, says senior author Dr. Patrick Keeling, professor in the UBC department of botany. “Imagine if you were an alien and sampled the Serengeti: you would get a lot of plants and maybe a gazelle, but no lions. But lions do matter, even if they are rare. These are lions of the microbial world.”

Using water samples from marine habitats around the world, including the coral reefs of Curaçao, sediment from the Black and Red seas, and water from the northeast Pacific and Arctic oceans, the researchers discovered new microbes. “I noticed that in some water samples there were tiny organisms with two flagella, or tails, that convulsively spun in place or swam very quickly. Thus began my hunt for these microbes,” said first author Dr. Denis Tikhonenkov, senior researcher at the Institute for Biology of Inland Waters of the Russian Academy of Sciences.

Surprise kilonova upends established understanding of long gamma-ray bursts

This Gemini North image, superimposed on an image taken with the Hubble Space Telescope, shows the telltale near-infrared afterglow of a kilonova produced by a long GRB (GRB 211211A). This discovery challenges the prevailing theory that long GRBs exclusively come from supernovae, the end-of-life explosions of massive stars.
Image Credit: International Gemini Observatory/NOIRLab/NSF/AURA/M. Zamani; NASA/ESA

For nearly two decades, astrophysicists have believed that long gamma-ray bursts (GRBs) resulted solely from the collapse of massive stars. Now, a new study upends that long-established and long-accepted belief.

Led by Northwestern University, a team of astrophysicists has uncovered new evidence that at least some long GRBs can result from neutron star mergers, which were previously believed to produce only short GRBs.

After detecting a 50-second-long GRB in December 2021, the team began searching for the long GRB’s afterglow, an incredibly luminous and fast-fading burst of light that often precedes a supernova. But, instead, they uncovered evidence of a kilonova, a rare event that only occurs after the merger of a neutron star with another compact object (either another neutron star or a black hole).

In addition to challenging long-established beliefs about how long GRBs are formed, the new discovery also leads to new insights into the mysterious formation of the heaviest elements in the universe.

The research was published today (Dec. 7) in the journal Nature.

Developmental genetics: How germ cells cut the cord from their parent

An adult specimen of the worm C. elegans and an embryo are shown. In the adult worm, the protein BCC-1 was labelled with a fluorescent protein (GFP) to track its activity.
Photo Credit: Uni Halle / AG Christian Eckmann

For the first cell to develop into an entire organism, genes, RNA molecules and proteins have to work together in a complex way. First, this process is indirectly controlled by the mother. At a certain point in time, the protein GRIF-1 ensures that the offspring cut themselves off from this influence and start their own course of development. A research team from Martin Luther University Halle-Wittenberg (MLU) details how this process works in the journal Science Advances.

When a new organism starts to develop, the mother calls the shots. During fertilization, the egg cell and sperm fuse to form a single new cell. However, the course of cell division, and thus how a new living being forms, is initially determined by the mother cell. "Regardless of the organism, cell division is initially pre-programmed by the mother," explains geneticist Professor Christian Eckmann from MLU. The mother’s cell provides a developmental starter set that includes the first proteins as well as the RNA molecules that serve as blueprints for further proteins. All this is necessary to jump start cell division and an organism’s development.

Big Bang research: ALICE experiment at CERN starts test operation with lead ions

The ALICE detector is being opened for an upgrade.
Photo Credit: Sebastian Scheid, Goethe University

The ALICE experiment at the CERN particle accelerator center in Geneva, Switzerland, investigates the state of matter shortly after the Big Bang, also known as the quark-gluon plasma. By causing lead ions to collide with each other, it is possible to create such a quark-gluon plasma for tiny fractions of a second. Now, for the first time, a test run at CERN for the ALICE experiment has generated collision energies of 5.36 teraelectronvolts per nucleon-nucleon collision – the highest collision energy ever achieved worldwide. Researchers led by Goethe University's Harald Appelshäuser prepared the central ALICE detector for these higher collision rates, which they hope will offer new insights into the origin of the universe.

A few fractions of a second after the Big Bang, all matter in the universe constituted a kind of "elementary particle soup", known as quark-gluon plasma. By allowing heavy ions to collide in particle accelerators, it is possible to create such quark-gluon plasma for an extremely short time. Such lead ion collisions are central to the ALICE experiment at CERN's accelerator center, which aims to study the properties of matter as it existed shortly after the Big Bang.

Staph infection-induced kidney disease may be linked to bacterial gene mutation

Anjali Satoskar
Photo Credit: Ohio State University

Researchers aiming to predict which staph-infection patients might develop a related kidney disease have found a high frequency of gene mutations in the infecting bacteria of affected patients, which suggests these variants may play a role in the body’s initiation of the renal damage.

The kidney disorder is a fairly uncommon autoimmune complication to Staphylococcus aureus infection. Although it is potentially reversible with quick administration of appropriate antibiotics and effective treatment of the infection, it can also lead to kidney disease or kidney failure.

“There are many varieties of autoimmune nephritis. For most of them, suppressing the immune system is the first line of treatment, but this type is unique because you have both an ongoing severe infection as well as this autoimmune tissue-injury response happening at the same time. Immunosuppression is not an option while the infection is still active,” said study senior author Anjali Satoskar, clinical professor of pathology in the Ohio State University College of Medicine. “It can be a diagnostic as well as a therapeutic challenge.”

In an exploratory study, Satoskar and colleagues found a higher frequency of mutations affecting a group of Staphylococcus aureus genes in blood culture isolates from patients with staph-associated nephritis compared to patients having staph infections without development of autoimmune kidney disease.

Scientists Discovered Late Antique Ice Age Was Not Global

Map of the study areas and examples of three anomalous anatomical structures.
Photo Credit: Monika Grabkowska

The international group of scientists, which includes Ural dendrochronologists, found that between 536 and 550 years the temperature decreased only in the Northern Hemisphere. Scientists obtained data on trees in Eurasia, the Western and Southern Hemispheres. The results were published in Science Bulletin. The work was supported by the Russian Science Foundation (project No. 21-14-00330).

"We estimated the spatial scale of the events of the 536-540s using tree rings. We used "abnormal" rings as markers. One advantage of the approach is that the width of the annual rings responds to temperature changes mainly only in the polar regions and highlands, but abnormal rings form during extreme cold spells in trees in many regions of the Earth. Therefore, the work included data on 23 different points, including the Southern Hemisphere, that is much more than when using the width of the rings," says Rashit Khantemirov, co-author of the work, Leading Researcher of the Laboratory of Dendrochronology of the Institute of Plant and Animal Ecology, Ural Branch of the Russian Academy of Sciences, and Head Specialist of the Laboratory of Natural Science Methods in Humanities at Ural Federal University.